Code converter



Dec. 2, `1952 A. SNIJDERS 2,520,395

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CODE CONVERTER Filed June 26, 1948 3 Sheets-Sheet ."5

V2 Bi Patented Dec. 2, 1952 UNITED STATES PATENT OFFICE Application June 26, 1948, Serial No. 35,403 In the Netherlands June 30, 1947 l Claims. l

This invention relates to a device for converting signals given in a rst arbitrary code into signals expressedin another arbitrary code.

The code-converter according to the invention comprisesa device for converting by electronic means signals from one or more codes of arbitrary nature into one or more other codes, the converter having for every signal element in the rst codes two indication points (contact), a certainstandard voltage being applied to one of these (identified as theY spacing point) or to the other (called the marking point) if the corresponding element of the applied signal is a space or mark, respectively; the standard voltagev may be ground potential. The nature of the device is suchv that if one of the indication points receives standard voltage, the other receives a voltage deviating from the standard in a single given direction, this direction of deviation being the same throughout the entire device.

If the converter is designed for the conversion of p signals an equal number of output conductors is provided, each of these being connected by n conductors comprising resistances to a variation of indication points corresponding to the variation of the elements of the input signal for which, when it is applied to the code-converter, the output conductor acquires the standard voltage, 11, being the total number of elements comprised in the signals in the rst codes, which are to be converted. rlhis first part of the code-converter constitutes the analyzer, indicating by standard voltage on one of p output conductors whichever of p input signals is beingA applied to the code-converter input. When reduced to practice the n conductors connected to each of the p conductors may form one junction. The remaining p-l conductors receive voltages deviating from the standard voltage in the standard direction, as will be explained hereafter. The analyzer thus converts from a code of n elements into a code of p elements having a contact space-mark ratio p1:1.

The device also comprises a synthetizing part ensuring the formation of a signal in the new code or codes with m elements In general, the conversion from a code having n elements, each of which elements has two indications (space and mark) thus comprising 2n variations, into p variations of a code having m elements, necessitates an analyzer in which the signals are first analyzed or converted into a code having p elements and then this code is synthesized or converted into the code having m elements. When thetotal number ofvariations of thecodeY having m elements exceeds 2n variations as allowed by the code having n elements, the synthetizing part for further converting the analyzed 2n variations, also may he provided with means for adding signals to the 2n variations of the code having n elements to make up the'difference between the 2n and p variations allowed by the code ofV m elements. If it is assumed that the code having n elements permits 2":.127 variations, while p variations are possible inthe code having m elements, the arrangement may be so provided that p' is a power of 2 which approximates theA number p. Thus one may express n in terms of p' by solving the equation 2:22 for n;

nzlogz p and substituting a common logarithm base in this equation instead of base 2, from the formula:

The device according to this invention converts from one arbitrary code into another practically without inertia, the only limiting factor to speed being determined by the speed with which the texts may be supplied to the device and taken from it. The action of the code-converter is static and it occupies little space.

The converter maybe adapted to denite codes beforehand by making the requisite connections cn a cross-connecting board.

This invention will be described with reference to two figures showing by way of example the conversion of a five-unit code into a seven unit code. It will be clear that neither the number of elements of the codes is limited to ve and seven nor is the number of codes limited to one.

Figure 1Y is a circuit diagram showing the principle of the converter;

Figures 2 and 2A show a complete circuit for the conversion for ve unit into seven unit code.

The principle of the code-converter according to Fig. 1 is explained in connection with the conversion of a denite signal from a five-unit code into another code, in this case with l-units, this code satisfying the special condition of having four spacing elementsin every-signal, 'as-may be required in a radiotyping system.

rlhe code may be supplied to the converter as punchings in a tape.

Contacts I-V in Fig. 1 represent change-over contacts in an automatic keyer served by this tape. Alternatively these contacts may belong to relays not shown in the figure.

The tongues of these contacts are connected to one another and to one of the poles of a voltage source V1, (ground).

The spacing and marking contacts which cooperate with the tongues I-V are all connected through equal resistances Risi-17o to the other pole of the source V1.

A conductor G3 is shown, by way of example for one signal, to be connected by resistances Rs2-Rea to a variation of the markings and spacing contacts of each of the tongues I-V. In Fig. 1 resistances Rs2 and Rss are connected to the marking contacts cooperating with tongues I and II, and resistances R36, R52 and Res are connected to the spacing contacts cooperating with tongues III-V. The resistances Rs2, R36, Rs2 and Rss may be assumed to be resistors in the description which follows. In the example of a five-unit code tongues I-V constitute 32 diiierent variations. For only one of these, conductor G3 will carry ground potential, in Fig. 1 for the variation having tongues I and II on the marking contact and tongues III, IV and V on the spacing contact. Through the tongues I-V ground is applied in this case to resistances Rs2, Rss, R36, Rs2. and Rss.

If a variation opposite to the one just considered is on the tongues the potential of conductor G3 will be as different from ground as possible. For all other variations of the positions of the tongues conductor G3 Will assume other potentials corresponding to four values intermediate between ground and the potential just considered.

Conductor G3 is connected to an output yielding the desired output code. In Fig. 1 it is a seven unit code. Conductors i-l end in an equal number of distributors VCI-1, which successively connect a discriminator circuit, represented by a tube Bl, to each of conductors |1 for examining their potential. Conductor G3 is connected with a predetermined combination of conductors I-1 by way of rectier cells e. g. Kill-i2 in order to prevent undesired couplings between the conductors l-l and thereby to connect only those conductors which are to receive the standard potential. The seven distributor contacts VCI-'I successively connect the seven conductors to a high-ohmic resistance R114 and to the grid of the discriminator tube BI in the anode circuit of which is provided a source V2. The other end of this resistance is connected to the negative pole of source V1.

The values of the elements are such that only for the characteristic of Fig. 1 conductors VCS, 4 and 6 will practically be at ground potential, the potentials of conductors VCl, 2, and 1 being indenite. Thus on the successive closure of the seven distributor contacts, tube Bl will be in non-conductive condition when the contacts I, 2, 5 and 'l are closed and conductive at the closing of contacts 3, 4 and 6, for when l, 2, 5 and 1 are closed and 3, 4 and 6 are open, the negative potential from V1 will bias Bl to cut-oit and in the other moments the potentials of conductors 3, 4 and 6 which are practically ground due to the relatively small value of resistances Rs2, R98, Ras, R52, Rss, and the high value of resistance R174 will result in the conducting condition of tube Bi. Fig. 1 does not show the manner in which the output code is utilized, this being no part of the invention.

w=35 variations 32 of which are formed from the five-unit code, the three remaining variations being generated on the operation of one of the contacts Sl, S2, or S3. Y

A conductor G as discussed already with reference to Fig. 1 is provided for each of the 32 vari.- ations; it is connected by iive conductors each comprising one of the resistances R1-1s0 forming a resistance matrix connected to the conductors G to five of the indication points, I-I. Points [-5 are identified as spacing indication points and points B-l as marking indication points. The connection is eiected in accordance with the variation corresponding to the intermediate output conductor considered.

For signal OOOOO consisting of five spacing elements, tongues I-V will occupy positions as indicated and thus apply ground to spacing indication points [-5, so that the uppermost horizontal intermediate output conductor Go receives a standard potential such as ground potential, namely over resistances R1, Rrr, R33, R49, R65. The second horizontal intermediate output conductor for instance will receive a diierent potential even though it receives ground through resistances R18, R34, R50 and Res, because through resistances Rai and R152 it receives the voltage of the other battery pole. On examination it will be evident that for every applied signal there will always be only one single intermediate output conductor at ground potential, namely that connected to the indication points I-I 0 in a variation corresponding to the variation of the applied signal.

In the embodiment shown in Figs. 2 and 2A of the drawing voltage is supplied to the indication points I-I by connecting each of these points through one of the resistances Risi-R to battery pole (of deviating voltage) and by connecting the tongue to the ground (standard voltage).

If E is received, for instance, tongue I will be on the lower contact and ground on indication point (contact) 6 and also on points 2, 3, 4 and 5 (as tongues II, III, IV and V will be at normal and battery will be on the other points which will therefore deviate in voltage). Thus the second horizontal intermediate output conductor receives ground potential.

The potential distribution over the 32 conductors is as follows:

A single conductor (the desired one) is at ground potential.

5 conductors are at a potential more negative by one unit level,

10 conductors are at a potential more negative by two unit levels,

l0 conductors are at a potential more negative by three unit levels,

5 conductors are at a potential more negative by four unit levels,

1 conductor corresponding to the variation opposite to the one considered is at a potential more negative by ve unit levels.

Each of the 32 conductors is connected through rectier cells to the variation of the 7 output conductorscharacteristic tov this horizontal intermcdiate output conductor. This may be chosenat will and mayfeasily be varied by means of a cross-connectingv board.

Owingg tothe connection of each of the 32 horizontal intermediate output conductors to certain three conductors of; the common set of '7 vertical code-converters an effect is produced which is not evident from Fig. l in which only asingle-output conductor with itsconnectionsis considered.

As. explained, three of these conductors will receive groundfrom. the horizontal intermediate outputv conductor` which itself is at ground potential; the other output. conductors will be,

as stated, at various more negative levels andv thev other vertical output code conductors will be connected to the. other horizontal intermediate. output conductors by connections containing. rectifying cells constituting a rectier matrix, which act in suoli a manner as to allow a vertical output conductor toassurne only the least negative, potential-of all of the horizontal intermediateoutput conductors to which it is connected. It is therefore highly probable, that the four vertical output conductors which at any time are not at ground potential will assume anegative potential not more negative than the rstnegative level considered above. This level should be suiciently negative to cut off the discriminating tube on the closure of the correspondingdistributor contact VC.

The` seven-unit code conditioned to three marking elements inv every variation comprises 35 diierent variations which are three more than the 32 variations of the five-unit code. These three additional variations may be controlled by separate contacts Sl-S3, the closure of any one of. Which completely cuts off the input control circuit. with the tongues I-V and applies ground potential to one of the additional horizontal intermediate output conductors gli-g3 which in its turn correctly marks threeof the seven vertical output code conductors through rectiners K9.-K99, Kills-Kw2 or KMS-Kids. As the resistance. and the rectiers are arranged in matrices the` conductors and connections thereon may be termed junctions.

Complicated code translations such as those required in some automatic telephone systems which determine from 3 or more given digits a quite different digit variation can be obtained by a combination of devices according to the invention. Thus an unlimited translation of number systems may bek obtained.

I claim:

lv. A device for converting signals from a code of ve elements into another code of seven elements, comprising in combination, ve pairs oi contacts; five members, each adapted to take twov positions in which said member applies a standardl potential to one of the contacts oi said pairs, respectively; means for app-lying potentials differing from the standard potential in the same sense to the contacts of said pairs Whic arev not at-standard potential; thirty-tivo output conductors; ve resistances for each of said ontput conductors connecting, respectively, said output conductors to a contact of each of said ninety-six input conductors; and means for connecting, respectively, to said output conductors an individualV combination of three of said input conductors.

2. A. device for converting signals from a code ofi veaelementsinto; another codeof seven elements, comprising in combination, live. pairs of contacts; ve members, each adapted toltake two positions in which said member., applies a standard potential to one of the contacts of said pairs, respectively; means for applying potentials diiering from the standard'potential inthe same sense to the contacts of said pairs which are, not at standard potential; thirty-two output conductors; five resistances for each of said output conductors connecting, respectively, said output conductors to a Contact of each of said pairs; ninety-six input conductors; and' meansincluding rectifier cells for connecting, respectively, to said output conductors an individual combination of three of said input conductors.

3. A device for converting signals from a' code of. ve. elements into another. code ofi sevenielements, comprising in combination, ve pairs of contacts; ve members, each adapted to take two positions in which said member applies a standard potential to one of the contacts of said pairs, respectively; means for applying potentials diiering from the standard potential in the same sense to the contacts of said pairsv which are not at standard potential; thirty-two intermediate output conductors; five' resistances for each of said intermediate output conductors connecting, respectively, said intermediatev output conductors to a contact of each of said pairs; seven output conductors; means including rectifier cells for connecting, respectively, to said intermediate output conductors an individual combination of three of said seven output conductors; a discriminator; and means for connecting said discriminator successively to said seven output conductors.

4. A device for converting signals from a code of .ve elements into another code of seven elements, comprising in combination, live pairs of contacts; ve members, each adapted to take two positions in which said member applies a standard potential to one of the contacts of said pairs, respectively; means for applying potentials differing from the standard potential in the same sense to the contacts of said pairs which are not at standard potential; thirty-two intermediate output conductors; ve resistances for each of said intermediate output conductors connecting, respectively, said intermediate output conductors to a contact of each of said pairs; three additional intermediate output conductors; means for applying a standard potential to said additional intermediate output conductors, respectively; seven output conductors; means including rectiier cells for connecting, respectively, to said intermediate output conductors an individual combination of three of said seven output conductors; a discriminator; and means for connecting said discriminator successively to said seven output conductors.

5. A device for converting signals from a code of five elements into another code of seven elements, comprising in combination, rive pairs of contacts; ve memberaeach adapted to take two positions in which said member applies a standard potential to one of the contacts of said pairs, respectively; means for applying potentials differing from the standard potential in the same sense to the contacts of said pairs which are not at standard potential; thirty-two output conductors; ve resistances for each of said output conductors connecting, respectively, said output conductors to a contact of each cf said pairs; three additional output conductors; means for applying. astandard potential to said additional output conductors, respectively; resistances connected, respectively, to said additional output conductors; and means for applying to said resistances connected to said additional output conductors a potential diering the same sense from the standard potential as those applied to the contacts of said pairs which are not at standard potential.

6. A device for converting p signals from one code having n elements into another code having m elements, comprising in combination, p conductors for the one code having n elements; m conductors for the other code having m elements; a rectiier matrix connecting said p conductors for the one code having n elements to said m conductors for the other code having m elements; and means including a matrix for indicating one signal of the code to be converted.

'7. A device for converting signals from one code having p elements into another code having m elements, the codes having a constant space-mark ratio, comprising in combination, p conductors for the one code having p elements; m conductors for the other code having m elements; and a matrix including a plurality of rectiers for connecting said p conductors for the one code having p elements to said m conductors for the other code having m elements, said rectiiers forming groups having equal numbers of said rectifiers, each of said groups being connected to each of said p conductors of the one code having p elements, the numbers of rectiers in said groups being in a predetermined relation to the constant number of marks and spaces, respectively.

8. A device for converting signals from one code having p elements into another code having m elements, the one code having p elements having a space-mark ratio of p-ltl, comprising in combination, p conductors for the one code having p elements; m conductors for the other code having m elements; a rectier matrix connecting said p conductors for the one code having p elements to said m conductors for the other code having m elements; and means including a matrix having junctions for imparting a standard potential to one of said p conductors by arbitrary application of control voltages to said junctions.

9. A static selecting device for converting signais from one code having 'p elements into another code having m elements, comprising in combination, p conductors for the one code having p elements, said o conductors being at different potentials With only one at a standard potential corresponding to the signal to be converted; m conductors for the other code having m elements; and a rectiiier matrix connecting said p conductors for the one code having p elements to said m conductors for the other code having m elements, and for connecting said standard potential to at least a predetermined one of said m conductors.

10. A static selecting device for converting p signals from one code having n elements into another code having m elements, p being an integer different from n, comprising in combination, p conductors for the one code having n elements, said p conductors being at diierent potentials with one at a standard potential corresponding to the signal to be converted; m conductors for the other code having m elements; and a rectifier matrix connecting said p conductors for the one code having u elements to said m conductors for the other code having m ele` ments and for connecting said standard potential to at least a predetermined one of said m conductors, said m conductors forming the' junctions at one end of said rectiers of said matrix.

11. A device for converting signals from one code having p elements having a constant spacemark ratio of p-lzl into another code having `m elements, comprising in combination, p conductors for the one code having p elements; m conductors for the other code having m elements; a rectifier matrix connecting said p conductors for the one code having p elements to said m conductors for the other code having m elements, said m conductors for the other code having m elements forming the junctions at one end of said rectiers of said matrix; a voltage discriminating device; and distributor contacts connecting said junctions, respectively, to said voltage discriminating device. y

12. A device for converting signals from one code having p elements having a constant spacemark ratio of p-lzl into another codehaving m elements having a constant space-mark ratio, comprising in combination, p conductors for the one code having p elements; m conductors for the other code having m elements; a rectifier matrix connecting said p conductors for the one code having p elements to said m conductors for the other code having m elements; and a resistance matrix for imparting potential levels to said p conductors for the one code having p elements, one of .said p conductorsfor the one code having p elements receiving a standard potential.

13. A device for converting p signals from one code having n elements rst into an intermediate code having p elements and a constant spacemark ratio of p-1:l and then into another code having m elements having a constant` spacemark ratio, comprising in combination, p conductors for the intermediate code having p elements; m conductors for the other code having m elements; a rectifier matrix connecting said p conductors for the intermediate code having p elements to said mV conductors for the other code having m elements; and a resistance matrix for imparting potential levels to said p conductors for the intermediate code having p elements, one of said p conductors for the one `code having p elements receiving a standard poten-tial, said resistance matrix having n junctions to each of said p conductors for the one code having n elements for imparting two control voltages to said resistance matrix.

14. A device for converting p' signals from one code having n elements rst into an intermediate code having p elements and a constant space-mark ratio of p-l 1 and then into another code having m elements having a constant spacemark ratio, p being an integer greater than p', comprising in combination, p conductors for the intermediate code having p elements; m conducltors for the other code having m elements; a rectier matrix connecting said p conductors for the intermediate code having p elements to said m conductors for the other code having m elements; a resistance matrix for imparting potential levels to at least p' of said p conductors for the intermediate code having p elements, one of said p conductors for the intermediate code having p elements receiving a standard potential, said resistance matrix having n junctions to each of said p conductors of the intermediate code having p elements for imparting -two control voltages to said resistance matrix from one end 9 of the resistances of said resistance matrix; ein-:l2

log p log 2 conductors, the other end of the resistances of said resistance matrix being connected to said 2 10e p loer 2 conductors, p being a number approximately equal to p which number is a power of 2.

15. A device for converting p signals from one code having 1L elements rst into an intermediate code having p elements and a lconstant spacemark ratio of p-l :1 and then into another code having m elements having a constant space-mark ratio, p being an integer greater than p', comprising in combination, p conductors for the intermediate code having p elements; m conductors for the other code having m elements; a rectier matrix connecting said p conductors for the intermediate code having p elements to said m conductors for the other code having m ele- `ments; a resistance matrix for imparting potenial levels to at least p of said p conductors for the intermediate code having p elements, one of said. p conductors for the intermediate code having rp elements receiving a standard potential, said resistance matrix having n junctions to each CES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,139,979 Haselton Dec. 6, 1938 2,279,353 Van Duuren Apr. 14, 1942 2,336,919 Zenner Dec. 14, 1943 2,369,474 Luhn Feb. 13, 1945 2,428,811 Rajchman Oct. 14, 1947 2,473,444 Rajchrnan June 14, 1949 2,476,065 Rochester July 12, 1949 FOREIGN PATENTS Number Country Date 499,909 Great Britain Jan. 31, 1939 

